This invention relates to a stem mechanism able to perform a switching operation and pushing operation.
In the conventional type stem mechanism, a hands adjustment, a date adjustment and a weak adjustment are operated by the operation of the winding shaft whereby the stem mechanism has a complicated construction because of the additional mechanism and increased number of parts.
Generally in a watch the stem mechanism has to be mounted in as small a space as possible according to the restricted space of the other mechanism.
FIG. 1(A), 1(B) and FIG. 2(A), 2(B) show respectively the conventional stem mechanisms, these mechanism are employed instead of the conventional trigger-piece and setting lever.
In FIG. 1(A), (B), the winding shaft supporting member 1 is mounted on the base plate by the screw bolt 2, and said winding shaft supporting member 1 develops a spring force radially of said winding shaft 4 by the bent portion of said supporting member 1 which is inserted in the hole 3 of said base plate.
Said winding shaft 4 is positioned by the bent portion 1b of said winding shaft supporting member 1 engaged with the recess portion 5a of the detent portion 5. The winding shaft supporting member 1 is moved when said bending portion 1b climbs over the protrusive portion or annular step 5b on the detent portion 5 by the pulling of said winding shaft 4. When said bending portion 1b falls into said recess portion 5c, said winding stem supporting member is positioned at a secondary step portion. However, in said stem mechanism, it is difficult to push said winding shaft without the operation of said detent portion 5.
In FIG. 2(A), (B), structure for the pushing mode of operation is added to the stem mechanism. The stem shaft 4 is positioned by the winding shaft supporting member 1 as indicated in FIG. (A), (B), and a force in the direction of arrow mark B is applied to said supporting member 1 by the restoring spring member 6.
The long recess portion 5d formed in the detent portion 5 of said winding shaft 4 for guiding said bent portion 1b of said winding shaft supporting member 1 when said winding shaft 4 is pushed whereby the switching operation of said winding shaft 4 and the pushing operation of said winding shaft 4 can occur. However, according to the embodiment in FIG. 2, it is necessary to provide spring member 6 for automatically restoring said winding shaft 4 in the pushing mode of operation. Further relating to the mounting space required for said spring member 6, the space loss becomes larger because of the guiding recess portion 5d.